1. Field of the Invention
Embodiments of the present invention generally relate to write heads for hard disk drives and in particular to a stepped pole for a write head used for perpendicular recording on a magnetic disk.
2. Description of the Related Art
There has been increasing progress in the field of magnetic disk storage system technology in recent years. Such success has made storage systems an important component of modern computers. Some of the most important customer attributes of any storage system are the cost per megabyte, data rate, and access time. In order to obtain the relatively low cost of magnetic disk storage systems compared to solid state memory, the customer must accept the less desirable features of this technology, which include a relatively slow response, high power consumption, noise, and the poorer reliability attributes associated with any mechanical system. On the other hand, magnetic storage systems have always been nonvolatile; i.e., no power is required to preserve the data, an attribute which in semiconductor devices often requires compromises in processing complexity, power-supply requirements, writing data rate, or cost. Improvements in areal density (the amount of information that can be placed within a given area on a disk drive), have been the chief driving force behind the historic improvement in storage cost. In fact, the areal density of magnetic disk storage systems continues to increase. Today, as the magnetic particles that make up recorded data on a magnetic disk become ever smaller, technical difficulties in writing and reading such small bits occur. Further, as areal density increases, the requirements put on head designs continue to become more challenging.
As the demand for storage has increased dramatically over time, technologists have worked toward increasing the amount of information that can be stored onto disk drives. By increasing the areal density, technologists have been able to deliver increasing storage capacity over the course of the last several years. A key end-result or benefit of this dramatic areal density curve is that disk drive manufacturers have also been able to reduce the cost of the disk drives themselves because they can offer higher capacity disk drives using fewer disks, heads, and mechanical parts. Increasing areal densities to allow greater capacities is no small task. As it has become more challenging to increase areal densities in longitudinal recording, to go to even higher areal densities, researchers are looking at several alternatives, including perpendicular recording. In recent years, the increased demand for higher data rate and areal density has driven the perpendicular head design to scale toward smaller dimensions and the need for constant exploration of new head designs, materials, and practical fabrication methods.
It can be seen then that there is a need for a write pole in a magnetic head that provides effective magnetic flux to the pole tip for writing to a magnetic disk, while avoiding leakage or fringing that can result in side writing and side erasure.